The use of surgical stapling as a method for suturing has increased dramatically in recent years. Staples have been used both internally and in the skin. The first staples used were metallic staples, and they are still widely used; see, for example, U.S. Pat. No. 4,321,002. For internal use metallic staples are frequently permanently implanted, while metallic staples in the skin are removed as soon as healing permits. For some purposes two piece staples are used wherein a fastening member and receiving member are used. Although these two piece staples were initially metallic, several polymeric fasteners have now been described, for example in U.S. Pat. Nos. 4,532,926; 4,534,352; and 4,534,350. A multi-part surgical fastener for inserting multiple staples in soft body tissue (but not skin) includes "absorbable plastic" parts and is described in U.S. Pat. Nos. 4,060,089 and 4,513,746.
Polymeric surgical staples designed for use in one piece are limited, but a one piece device using a hinge and cam principle is described in U.S. Pat. No. 4,428,376. U.S. Pat. No. 4,317,451 discloses plastic surgical staples which can be made of totally absorbable or totally nonabsorbable materials.
The type of staple commonly used for stapling skin is different from most other staples. Skin staples, to be closed, are acted upon by forces only from one side of the stapled medium, whereas other types of staples are acted upon by forces above and below the stapled medium. Such skin staples may be supplied singly or in array for use in a cartridge or stapling instrument. An example of an array of metallic staples bonded together by a biodegradable absorbable plastic is found in U.S. Pat. No. 4,275,813.